In time, I assume the Rohrbaugh brothers will bring to market other profitable stuff.
As to what comes with the gun, a take-down block/unloaded chamber flag would be nice.
As to rods, I can see Rohrbaugh contact Dewey and contract with them to produce a short coated rod just for the Rohrbaugh. By selling the Dewey rod, they would open up another profit center. They are not cheap ($25 retail), and they would have a nice mark-up. (I would buy 2.) They may also carry brass or plastic "stick" rods as a lower cost item.
Short term, I assume the Rohrbaugh brothers will begin to carry holsters, since people are more likely to buy a pistol if holsters are available. I also assume that they will feature replacement mags and recoil springs on their web site. Later maybe small travel gun and ammo cases, et cetera.
I would also expect grip panel options being made available, but as for myself, I like the carbon fiber panels for their weight.